Plastic sheet folding machine



Nov. 8, 1949 R. F. TABER PLASTIC SHEET FOLDING MACHINE 6Sheets-Sheet 1Filed Feb. 6, 1947 Nov. 8, 1949 R. F. TABER 2687,4953

PLASTIC SHEET FOLDING MACHINE Filed Feb. 6, 1947 e Sheets-Sheet 2 Nov.8, 1949 v R. F. TABER PLASTIC SHEET FOLDING MACHINE 6 Sheets-Sheet 3Filed Feb. 6, 1947 /NVENZ'0/Q w I ATTOR/VE Nov. 8,' 1949 R. F. TABERPLASTIC SHEET FOLDING MACHINE 6 Sheets-Sheet 4 Y Filed Feb. 6, 1 947 npm Nov. 8, 1949 v R. F. TA-BER 7 2,487,495

PLASTIC SHEET FOLDING MACHINE Filed Feb. 6, 1947 6 Sheets-Sheet 5 r //vvm r02 A TOQNEY R. F. TABER PLASTIC SHEET FOLDING MACHINE Nov. 8, 1949 6Sheets-Sheet 6 Filed Feb. 6, 1947 Patented Nov. 8, 1949 UN I-TED STATESPATENT OFF ICE PLASTIC. SHEET FOLDING: MACHINE Ralph F. Taber;"Bui'ialoi'fii' Y.

Application February ,6, 1947;.Serial-"N'. 26,918-

Thisinvention relatesto. amachinefor forming.

folds in plastic sheets.

'llheinvention comprehends amachine for foldingsheet.materialsprovidednwith arheated. folding blademounted forreciprocating movement to and-froma'positiorrwhere it operates incooperation withado-acting fold forming means to permanently. form. afold. through the. timed operation of. the heated folding. bladeengaging and folding thesheetin the fold. forming. means where it isadapted tobe retained until-the fol'd is permanently sets in. the sheetmaterial.

The invention provides a. machine for rapidly folding plastic sheetmaterial having, a heated foldingblade movable toward and from afolding' position where a sheet to. be folded" is supportedona pairiof.fbl'd forming bars,.at least one of. which. is relatively movableto the.other. in a direction substantially perpendicular to the movement ofthe. folding blade. The folding blade is moved to engage asheet'to befolded between the fold forming bars inspace'd' apartposit'ion'. Thefolding. blade is then moved slowly between the separated foldformingbars to bend the sheet while .it' is heated; As the. sheet" is softenedbythe heat at the corners of the blade, the'f'oldis formed around theend ofthe blade. The bars are held in the same spaced position while thefolding blade moves to its" full folding position therebetween. Thesheet does" not engage" the sides of the" folding-blade, only. thecorners at thefree' edge; The" blade is then withdrawn from thefoldportion; the sheet being retained between the" bars which are thenmoved closer-together to bend thefoldp'o'rtion of" the sheet tobringth'esheet porti'onsat opposite sides of the fold into close contact whilecooling the heated portionsof the'sheet so that a-"permanent completefold will be formed. When" the fold portion" of the sheet hascooledandset, thebars aremoved apart to their initial position todischarge the folded sheet.

The invention further comprehends a machine fbrfolding'plastic materialhaving a reciprocating folding bl-ade' movable to and from a foldforming position in cooperation with a-* pair of'f'oldforming.barsmovabletoward and from' each other in-timed. relation withthe folding blade; a mac'hlnehavin'g'a frame provided with pivoted arm'scarrying the folding'" blade for its reciprocating movement relativetothe forming bars, a top portionfon the frame" for supporting sheetmaterial to be folded between the folding blade and forming bars; and"a" carrier pivotedon' the framezan'd having atop portion" carrying. oneofl'theforming bars for movementrelative to. the other forming barmounted in opposed relation thereto .on. the frame aimachine wherein theforming bars may have: fiIlGuHlOVBHlGHt of the one mountedon the carrierrelative. to the other forming bar varied relative to the movement ofthe folding. blade for varyihgthe folding cooperation obtained betweenthe bladeand the. formingbars; a machine having the foldingblade.mounted on the frame for reciprocating movement and arranged-foradjustment on the. frame relative to the forming bars carried thereby sothatthe fold forming portion of the folding blade may, be. adjusted intocentered position betweenthe spaced parallel forming bars in eachadjusted position of operation thereof; a machine wherein theformingbars areprovided with resilient sheet engaging strips on theopposed'faces. thereof for. cooperation in folding and retaining, thesheet between the forming bars While the fbldin'gbladais withdrawn fromthe fold portion therein, and to further hold the portions ofl'th'e"sheet at opposite Sides of the fold closely together while the formingbars and resilient strips absorb the heat transmitted to the shee'tbythe folding? blade for. cooling andsetti'ng the fold inthe' sheet; asheet folding'ma'chine wherein an operating lever is provided foroscillating movement from and to a starting position for moving thefolding blade and'for'ming bars'toengage and fold a sheet between saidbars; a sheet folding machine having means controlling the movement ofthe folding blade and forming bars relative to each other so themovement of the folding blade isat'a substantially slow rate-asthe bladeengages and folds a sheetbetween the forming bars; a machine wherein"suitable" means. is provided for returning andtimingthereturn movementof the operatinglever to the starting position to secure'a slowwithdrawal" of the folding blade from the foldportion in the sheet withthe retention of the sheet between the forming bars for a period of timeafter the'folding'bl'a'de has been withdrawn, to tightly, foldthe-sheetand absorb the heat in the fold portion; and-"to-provide means forencasing the heated folding blade structurein a manner that willprovideeffective protection of the heated folding blade-for reducing thelikelihoodiof' injuryto an operator ofithe-machihe;

In the drawings"? Fig: I shows the foldingmachin'e constructedaccordingrto the invention in sideelevation; looking at theiri'ght-handside, with the major portion of the right-hand side" coverbroken away toshow details" of construction.

Fig. 2 a view similarftoi Fig; 1, showing: the

Fig. 6 is an enlarged fragmentary vertical H cross-section taken on line6-6 of Fig. 3.

Fig. 7 is a wiring diagram showing the circuit connections for thefolding blade heater and thermostatic control.

Fig. 8 is an enlarged diagrammatic cross-section illustrating theposition of the folding blade and forming bars at the beginning of asheet folding operation with the edge of the folding blade engaged witha sheet to be folded.

Fig. 9 shows the movement of the folding blade from the position of Fig.8 in folding the sheet between the forming bars with the folding bladein the full folding position between the bars.

Fig. 10 shows how the sheet is heldbetween the portion I2 extendsforwardly to the front of the frame. This formation of front wallportions I0, II and I2 provides a chamber at the front of the supportingframe below top portion I into which folded sheets may be discharged andguided to the front of the machine where the operator can remove them. Aguide plate I3 formed to fit wall portions If], I I and I2 is mountedagainst the front faces thereof, as shown in Fig. 1, and has an upwardlyinclined lip on the forward edge to facilitate the guiding and removalof a folded sheet from the frame.

. means of bolts or the like, as shown in Fig. 6.

forming bars by the resilient strip members as the folding blade iswithdrawn from its maximum fold forming position shown in Fig. 9.

Fig. 11 shows the position of the folding blade after it is withdrawn toa further extent from the fold and the sheet engaged and held betweenthe forming bars, together with a showing of the forming bars movedcloser together to engage the fold portion and bend it to hold theportions of the sheet at opposite sides of the fold closely engagedduring the period when the forming bars absorb the heat from the sheetmaterial and the fold in the sheet takes its permanent set.

Fig. 12 shows an edge view of a sheet completely folded in the mannerillustrated in the enlarged diagrammatic cross-sections in Figs. 8 to 11inclusive.

The improved sheet folding machine is particularly adapted for foldingplastic sheet material, such as Celluloid, and has a base I providedwith side members 2, a rear wall 3, while shoes 4 mounted on the lowerends of side members 2 rest on a floor in supporting the machine.

A rigid supporting frame 5 is mounted on the upper end of base I andrigidly secured to the side members 2 and rear wall 3 to form a, rigidstructure. Supporting frame 5 has spaced substantially parallel sidewalls 6 depending from the sides of a flat sheet supporting topportion 1. Flat top portion I is formed with a centrally located channel8 extending from the front to the rear portion thereof for receiving theguiding and retaining mechanism carried by gauge bar 9 so constructedthat gauge bar 9 may be adjusted with respect to the folding mechanismhereinafter described for gauging the distance between one edge of asheet to be folded and the fold portion to be formed therein.

The front edge of top portion 1 and side walls 6 terminate rearwardly ofthe bottom front portion ofsupporting frame 5 and a depending front wallportion I0, see Figs. 1, 2 and 6, extends downwardly from top portion 1between side walls 6. Front wall portion I0 merges into a downwardly andforwardly inclined front wall portion I I. The lower front portion offront wall portion II is formed to merge with a horizontal wall portionI2 spaced abovethe bottom of supporting frame 5, as shown in Figs. 1, 2and 6. Horizontal wall The other fold forming bar I5 is mounted in aseat It formed in top wall portion ll of a carrier I8. Side extensionsI9 on the carrier depend from the sides of top wall portion I'I beyondthe outer faces of side walls 6 of frame 5 and are rotatably mounted ontransverse shaft 28 havin opposite ends extending through side walls 6in which the shaft is suitably secured. Suitable bolts or the like, asshown in Fig. 6, rigidly secure the other fold forming bar I5 in seatI6.

Top wall portion I! of carrier I8 is formed to lie in the samehorizontal plane as top wall portion I of frame 5 to provide a flattopsurface for supporting a sheet to be folded with the rear edge againstgauge bar 9 to gauge the position of the fold in the sheet. Each foldforming bar I5 has the face thereof opposed to the other bar formed witha channel 2| having an'angular bottom wall formation, as shown in Fig.8, for example, to receive a resilient strip member 22, in the mannershown in Fig. 8. Each resilient strip member has one margin seated inthe upper portion of the channel against one angular face of the bottomportion of the channel, while the other margin of the strip is engagedin the channel with an inner portion extending inwardly beyond theadjacent face of forming bar I5, as illustrated in Fig. 8. The innerportion of the lower margin of each strip 22 is spaced from the angularbottom portion, as illustrated. These resilient strip members 22, one oneach fold forming bar I5, are arranged on the opposed faces of bars I5,as shown in Fig. 8, to provide gripping members arranged so the lowermargins of the strip members 22 will grip the outer faces of a foldedsheet therebetween, in the manner shown in Figs. 9 to 11 inclusive, andretain the folded sheet between the fold forming bars. These stripmembers resiliently grip a folded sheet in a manner sufficient to holdthe sheet while the folding blade is disengaged from the fold therein.By having the margin of each strip member 22 which engages a foldedsheet, spaced from the angular bottom portion of channel 2I, it will beunderstood that in addition to the strips being flexible, they areflexible in the channel relative to bars I5. The upper marginal portionsof each strip 22 are rigidly secured in channel 2 I, as shown.

A cam shaft 23 is rotatably mounted in bear ings in side walls 6,projects through the supporting frame with opposite ends projectingbeyond the opposite side walls of the frame. A cam 24 is rigidly mountedon the right-hand end of cam shaft 23 and has a roller 25 carried bystud 28 engaged with the periphery thereof. Stud 26 -:otatably mountsroller 25 on a rearwardly extending portion of right-hand side extension59 of carrier I8, carries stud 26 and roller 25, as

Fig. 1, and the opposite endsecured to"a pirr mounted Qn-right-handsidewall 5 6 of: frame 5. Spring 3lJ- normally ho-lds follower -roller=25i1en gage-d with 'the periphery of cam- 245 -in order to roekca'rrier 1 8'- "With its formingbar I 5 i'elativ'e atoi--tlie-iorming-bar carried loy the'-'- framer T' oppesite en'dof-camshaft'fl has a ratch-et wheel-W l rigidly mountecl thereon as shown in E932." A pair of plates 32 each have one end rotatably' mountecl on can-rshaft 23 for independent 'operation -re=latiVe--to' one another betweenratehet- -=wheel- 3l and= left-'hand-side wall 6: spring pressed epawls3 3 are pivotally mounted onth'e outer ends of-plates32 Pawls 33 arenormally-hld'iin engagement with the periphery of: ratehet wheelt maymeans-of the springs on pawls 33-and-plates-32 Az-"Parm supporting-shaft34 is-mounted "in transversely extending relation in frame 5 at'theupper--rear-portion thereon-as shown for examplet'in -Figswl and 2,-Withopposite ends extend-* in}; through side" walls 6 and: carrying blade sup portingarms=35 onth'e free ends thereof adjacent the outerfanes ofsidewalls 6 for pivotal-move mentrelative" -thereto-oneccentrica'lly'mounted bearings 3 81 The in' nen-baring memberhasan I eccentricmountingon the end of shaft 34',-"While the 'ou-te'r bearing-memberismounted in the free" end ofblade supporting amt 35; as shown -'in'- Fig:2 for-examplel" The-opposite" ends 'of bla'de".= supporting naz'ms 35zextend forwardly and: upwardly to the front portion of the machineabove top porti-o'n-l 'wh'ere'theycarrythe folding blade assembly 31$The folding blade assembly 3 l includes a body member 38'extendingbetweemand having opposi-te ends securedto the-free front endsof arms 35 5- Theidower-edgeof body '38 is provided with" a *seatforcletachably =receiving and"-mounting one-marginof foldingbla'de-39whilethe opposite 7 margin deperrds' below 'body -38 and -provides afree margin-adapted for I sheet folding coper'atio'n-with f0ld formingbars A heating ele"-"-- ment- M is mounte'd in body 38' of the foldingblade assemblyin any suitable manner; Heating ele'ment tfl is' aconventionaldorm of "eleotri'e heater"adapted'idr."connection in circuitwith'a sourceof-electric currentsupply in a manner't'hat willbeherein-afterdescribedr Heat indicator -4 is mounted on the blade?supporting arm' on the le'ft hand'sid'e ofthemachineand has a portionthereof. projectin'gdnto body 38 'for register-ingthe heat. therein Athermostat: control 'of conventi'oha'l: type: is lshown at142'mountedinn-the right-i: hand-tend ofl'folding blade-assembly 31'; as clearlyi.showminrliignix. This thermostat COI'ItI'OI TiS -COH-Inecttedsimtheelectric, circuit to' heating element 40, is responsive tothetemperature of:the hoidyi: Sill-$08 asntozs-zcontrols tlreaelectrie'lcincuit for-the heating= -element-;in:-;a mannerwell-:knownin :the: ant-to maintainrbodyfiflwat a desiredtemperaturezaccording; to .qthew adj ustmentuof rather-thermostats control.

Tlie operating mechanisnrioifireoipmceitihwiinn foldingblade and'foldforminmbarsrhasvamepemt atingshait r43 ibtaltably meunted inlsuitableibeame ings -in sid'e walls 6 and:dsi'locatedulmstli:rfrbntait:

ortions-or riginirsuppomingztframeniaasncleanmr shown in Figs. 1, 4 and6. Thebearings fontshafitii' 43zlmountedmimrside walls 3:6aiter'zindicatedlamfl,

14.:1 The endszioftoperatingsshafitizflzzmojebtzt outwardlyobeyondssidewalls m6. i Tlivdeft-hand endrofmperating shaft;A3ecarriesriana-ctuatiage; lerenzfl 5: and atheuright hand endecamties saniactmeatingzleyendfipasxzshown in Figstiyfl rfi- -e' 0? r atingt letvendfi:hasna iiorwandlyqpxtendingtimmit 41 2 andactuating; leveml 6: has asimilar construeer a tiontot'pnevidea pivotecormectionrfortmountingn one16nd .of: eachof a,pair'of-1links=148 on leversr: 45;land-:1.46;-:%respectively;y The opposite -;ends' of? links 48 are;pivotal-1y= connected; to the 1 upper-arr end DQIfEiOnS-of bladesupporting arms 35mm catedrat=49a @Themndensides otlarmrfl-landeleiler46 nearthe forwardendy carry QbSCI-.WS' sit-me, justablymounted-(therein tron engagementzwvitlrii the: horizontal top tpQntion-;of- :side members-:2 limitingathe rockin-g moyement ofalevers. sands.45m A pairtotlinks fi Lara pivoted-tether rearaend-L.ofs-actuating-lever 45gas shown in Figs-t2 and-sate. the opposite ends.are each zpiyotally connactedw to the f me end of vone x-Qf:theriplatest 32-l-\so:as ton connect actuating. f-levere. 45lwith-rboth," plateau-132.: in order to; simultaneouslyi :soperated:1,spLinens; pressed pawls 33M, A set; screwr52l-is ethllead-fids-inithezlowe-r rear .end portion of actuating-lleveled5mm engage thevtop.portion ofitsiclewmember. -;f a? limiting, ;-.the stroke.v of"movement-of actuating-5 lever 45 'in a counter-clockwise directionelasah shown in Fig.2... This limitsythe strokeofsmove= ment 4 of!spningl-rpressedwpawls e3 af-with. .s etxscrew-e seam ,alsoldeterminesathel stroke oftmovementz' of ,bladefia m.

An. operating; lever. 53" has one. end. mounted one the central portionof operating shaft 435,. whilee thelother end.extends-downwardly toflthelower front .portion ..of -.thelbase .structure where. -footlpedals b54', are mounted-thereon. in laterally"ex le: tendinarelationr-Theuppen,endl-portionrof npen s ating: lever ,53vhasaa 'laterally,extendingepliojecev. tion receiving one end of a rod :5firmounted"therein andxextending rearwardlytherefrom.- The opposite end of rod 1 56-=m0unts;a weight. 51*; 5 Weight 5'! is detachablylsecuredIto/rod"Shinranyr; suitable manner andvicarriesra pin :58,'kas-.-shownin Fig. 4; detachably ;mounting the "free ends. piston r0d 159'- of:adash:lpotwmechanism; Pistcni' rod, 59 is slidablygmounted and. :carriesa piston-t in; a .cylinderrfios The lower: end sofa: cyiinderscfilh is:pivotallyysecure d atwtfi lzitoi a bracket 62"? mount ded on rear wall3 of the basen..-.- v

A suitable guard? structure;- is eproyzidedritozrenclose; and protectxthefolding blade? assembly? else-generally indicated 813163;Thifigllfifl'diYStIlIc turel includes an; inverted;-:rsubstantially Ushaped; casing-dim enclosing -the foldinga blade assembly; andextending:transversely: acrossxthermachinezabove-the .frontaportion :of:top;:portion $1 as? shown? in-.-Figs; 3 and 6. Rearwardlyextending:ca'singzl portions '.6 5." are rigidly -secured:-. toopposite"ends; of and support casing;;;,64. 3 Casing portions-$5; have thealoweredges mounted ontheeupper side: edge portion :of sheetssupportingvtop':portion; :1 andleeachw has an outwardlyeextendingflange; :on the upper,- curvededg ezportion tthereofe;

Sideeovers wearer hinged alongethe-rearredgesa tOktIle 'TeaIY/Side;portionsnof nsupporting iram'ew and-ane-shaped tmenclose:themeehanismxahthee sides of frame 5 and to cooperate with the ends Band4.

The lower front portion of frame 5 is formed in the central portion toprovide a switch box 10, Fig. 4. A cable H carries the wires from switchbox I to heating element 49 and thermostat control unit 42, while cable12 carries wires from switch box 19 to a connector socket 13 forreceiving a plug connection from a source of electric current supply. Aswitch plate 14 is mounted over the front open end of switch box '10 andcarries control switch 15 and pilot lights 16 and 11. Pilot light 76 isconnected in the current supply circuit for heating element 49 and iscontrolledby switch 15, so that whenever switch 15 is closed to connectthe heating element 40 in circuit, pilot light 15 will be lightedindicating that the circuit is closed. Pilot light 11 is connected inseries with thermostat control 42 for indicating when the thermostat isclosed for closing the circuit to heating element 40. mostat control 42also has a series connection in the current supply circuit with heatingelement 40 in order that the current supply will be interrupted by theoperation of the thermostat control whenever the heat in the foldingblade assembly reaches the desired temperature. Pilot light 16 goes onand off, indicating when thermostat control 42 is operated to close thecircuit to heating element 40 and when the circuit is open.

A condenser 18 is connected in circuit in parallel with thermostatcontrol element 42, as illustrated in Fig. '7, for reducing arcingacross the contacts of the thermostat control element when the circuitis broken in a manner well-known in the art.

Figs. 1 to 4 show the machine in the starting position ready to begin afolding operation. With the electric circuits in the machine connectedto a source of current supply, the operator operates control switch 15to close the circuit to the heating element. This is indicated by pilotlight 16 becoming illuminated. In starting the machine, heating element49 will be cool and therefore the thermostat control 42 will close thecircuit to heating element 40, in view of which pilot light Tl will alsobe illuminated. The operator allows the current to heat the foldingblade assembly for a sufficient length of time until pilot light 11 goesout, indicating that the heat of the folding blade is at the propertemperature for folding.

- The operator sets the gauge bar 9 to the proper position and thenfeeds a sheet from the front of the machine so that the rear edge willengage gauge bar 9. Then the operator places a foot on one of footpedals 54 and moves operating lever 53 rearwardly until set screws 50engage the frame and limit further movement. In the starting position,fold forming bars are spaced apart, as shown in Fig. 8, with thelefthand bar in dot-and-dash line position. Cam 24 is in the positionshown in Fig. 1 where one of the dwells i8 is engaged with roller 25.

As soon as the operator begins movement of lever 53 toward the rear wall3, upward movement of the rearwardly extending end of actuating lever45, as shown in Fig. 2, will move links 5| upwardly and actuate pawls33. In this move- Therment, the left-hand pawl 33, asshown in Fig. 2,will engage one of the teeth on ratchet wheel 3| and rotate cam shaft 23and cam 24 to move the dwell I8 out of engagement with follower roller25 and bring one of the four intermediate peripheral cam portions 79into engagement with follower roller 25. At the same time, links 43operate blade supporting arms 35 to move folding blade 39 downwardlyuntil the free edge engages the upper surface of the sheet to be folded,as shown in Fig. 8. This occurs just prior to the operating leverreaching the rear limit of its stroke of movement and just before setscrews 50 engage the frame.

In the meantime, carrier 18 has been operated to move folding bar l5thereon inwardly to the full line position shown in Figs. 8 and 9, dueto intermediate peripheral cam portion 19 engaging follower roller 25.Cam portion 19 is concentric to the axis of shaft 23, as shown inFig. 1. The heated blade has a square free edge to engage and heats thesheet material at the fold as it moves from the position shown in Fig. 8to that shown in Fig. 9 so that, with plastic sheet material, thesubstance from which it is made will be heated at the corners alongopposite sides of the folding blade to a softened condition sufficientfor the material to bend freely without creating internal stress. Thecurved sheet portion will bend under tension in spaced relation to thefree edge of the folding blade, as shown in Fi 9.

The sheet being folded will have the portions at opposite sides of thefold extend upwardly along the upwardly and outwardly inclined portionsof strips 22 and the upper edges of bars I5, as shown in Fig. 9. Theseportions of the sheet above the fold will not engage the sides of thefolding blade above the lower corners. The position of the parts shownin Fig. 9 is obtained when operating lever 53 has been moved to the rearlimit of movement with set screws 50 engaged with the frame. Thisposition of the folding blade may be changed by adjusting set screws 50.

Then, the operator removes his foot from operating lever 53 and weight51 operates to return the operating lever to the starting position shownin Fig. l. The speed of return movement of lever 53 is retarded by theoperation of the piston in cylinder 36 by controlling the air dischargevent 3| at the bottom of the cylinder. During this return movementactuating lever 45 has a counter-clockwise rotation, as shown in Fig. 2,in which the rear end moves downwardly drawing links 5| downwardly withit. This causes spring pressed pawl 33 on the right-hand side of ratchetwheel 3|, as shown in Fig. 2, to engage one of the teeth on the ratchetwheel and continue rotation of the ratchet wheel in a clockwisedirection, as shown in Fig. 2. This continues rotation of cam 24 in acounter-clockwise direction, as shown in Fig. 1. In the initial part ofthe return movement of operating lever 53, folding blade 39 will bemoved, as shown in Fig. 10, out of the fold in the sheet which is heldby resilient strip members 22 in position between fold forming bars 15.Fold forming bars l5 are retained in the same spaced position shown inFig. 9 in providing the holding action on the folded sheet while thefolding blade is withdrawn.

Then, as operating lever 53 moves an additional distance forward towardthe starting position, folding blade 39 moves upwardly into disengagedrelation from the fold and from be- 9 tweenbars l 5,, as showfrinfull'li'nesin ll-- and then farthergup to: "the" position shown-in-"dtand-dash linesiin Fig. 11. When .foldingblade :39 reaches'thefull line position showntinFig. '11, cam 24 is rotated.to bring-camlobe80-into-enc, gagementwith follower-gro'lleri25 andt'move par- ;"rier'flsto bring forming bar 15 carried" thereby, still Icloser to the otherforming ,baJSIES shown in Big; 1 1. The portionof.fold'f.ormipg'"bars{I5 below'strips "22 wiil bend the 'curved pfofld'portion in thefsheet to a greater extent to bring the por- .'..tions,of, the sheetqatopposite.sides of. thejfold I together in'jclosecontacting relation.."Fold.form- I ing.barsl5 will simultaneously absorbthe heat .from the fo d. portion ofthesheet. Inthis way, "the sheet will.be rapidly cooled so that the plastic material will set inthe foldedposition 'and hold "the sheet portions on opposite sidesfofthefold 1.iniclose surface contact with one .another.

"Then, as operating leveri53.reach'esithefobward position, shown inFig.1, where. set screw .52 engages the frame to limit'the forward move-Lment of the operating lever, carrieri18.with its J. folding bar will bemovedi'ntothe dot-and-dash Ziline positionfshown infFlg'. '11, by reasonof'cam )124 being-rotated so'that the next dwell 18"therein 'willreceive roller 25. 'f'The" folding blade will be .at its. upper, limit.of movement, as shown iii'Fig. 1 .andsetscneW '52,- asishown in Fig: 2,willengage {the frame and limit further forward movement .of operatinglever 53. Whenthis point is reached, the ,Lfolded. sheet. between bars|5..will drop through between the.v bars] down the" inclined ,frontportion .ofthe, frame against guide plate II 3 Where ,it will.'slide...forwa1idly to'. the. front. edge ;..of theguide plate forremoval by'fithe operator. This operation of ;the, machine ,is'suchmasrto ...pro.duce. contact, of' folding, b1adei39 with. the.Lshelet;to sofiten'the material in .the. -.portion..to Joe ktold'edwhile the. blade. moves ratheryslowly tin 'iolding the sheet.betweenforming .shars ..;I 5, Join the. manner .clearly shown inFigs.18..to,.11;inclu- -....sive., Sufificient time is providedior.engagement "-of folding-blade. withthe sheet-so thataroom- :plete. foldis formed after-whiohmhesheet ,islheld l -by the folding; bars :during:the dissipation of the heat therefrom. The sheet -is :then l discharged'and'will have anedge .view in elevationg-xas shown win-Fig.12;:forexample.

i The invention claimedis: a .1. A plastic sheet :folding machine.comprising a'support; a heatedfolding blade, al pair of-iold formingharsmounted .for movement; on at least 1 one toward-and from the other :-onsaid support, i=-.;:ar-m. means-pivoted -on-.-said vsupport .andearr-ying saidtoldingblade for movement toward and from sssaiclabars inadirect on substantially. perpendicul.ar-'to the-plane of movement ofsaid-one bar, an operating lever. mounted athoneuzendnvon. said supportfor, oscillating movement, an.v actuating" a lever connected with said:operatingvlever ionoscillation lthereby a. link. connecting..said...actu

.atina. leverv and said. arm means .ior moving said folding. .blade.into cooperativeisheet' io'ldins; :re-

.lation. with said bars in movement ofgsaid .operatling. and. actuatinglevers "in: one direction and away fromsai'cl bars in movement ofsaidlevers in lithe. oppos te direction. and" means operated by saidactuating lever operable to move said movable .foldforming.bar"towardrsaid.otherbar a "lim ted amount in'the movementof'said actuating "lever-in "said onedirection and for moving; saidmovable bar closer :to 'said otherbar'in: move- -ment of {saidactuatingdeverzinsaid? oppositefdi rection in timed:relation"'with-"the---movement' of" said blade whereby said bla'deengages and iolds a sheet between said bars andthe'-movement-:bf saidbars closer together torms a tight/" field in sad sheet 'and' retainssaid sheet -th-erebetween 5 -as s'aiolfolding blade=movesaway"fromxseiid bars.

1 2. -A plastic sheet iolding machine, comprising a support; aheated-folding blada a: pairmf tzidld 1 formingbars mounted for movement'oF-at least one toward and from theother on said support,

a-pai-r of arms-pivoted onsaid support and oarr-yi-ngsaid' f oldingblade 'for movement-towardaand from "said; bars in-v adirectionsubstaritiailyaqaerv pendicular-to tha'plane of-movement ofsaict'one -doar,--:anoperating lever mounted at one eiid on said supportfor oscillating movement, :amactua-ting lever connected with saidoperating lever foroscillation theretw; a link- -connestingersaidactuating' 'lever with one of said arms for-moving= said folding-*blade-i'nto cooper'atives 'sheet folding relation with' saidv'barsin-movementifof said 'operating- =andactuating- 1eversin tonedirectionand away from said.- -=bars-in movement= bf i said levers inthe? opposite direction; and cam means operat'ed byasaid -actuatinglevefziors moving=said movable fold forming ban aflimited. dis- P tance"toward said other barewhen said; actiiating lever is moved in onedirectionrto'movesalid tolding blade toward said bars to engage ae'she'et i -therebetween to cooperate ininitiallycfoldin waid sheet, saidcam meansmovi-ng sa id: movable bar --an= additional distance towardsaid other; barn-in movement of said actuating; member -in -sa'id opfposite direction 1 for-"T-rightly foldingazsaiid isheet between saidbars while sa'id: folding bladewisl dis- 5' engaged-fromthe' fold insaid: sheet and zmOVTEd away from i said bars.

3. -A plastic sheet folding-machine;compris ng a s-upport; a heatedfolding blade; a' pair-bf fold -'1formingabars' 'mounted for movement ofat "least tonne-toward ahdrfrom theother onwaid-support, a pair of armspivoted on sa id support and'earr-ying said folding blade formovemeho'toward and from said bars in a" direction substantiallyperi"pendidular to thaplane of -movemeht ofi :said'one 1 bar;- anoperating lever mounted. at one end-: on said suppdrtfonoscillatingmovementsianw actuating lever conneetedwithsaid'operating-leven-tor "osc'iilation thereby; alink conneo'tingsa dactuatil ing' lever with onex'of said arms fonmoving said tolding bladeinto cooperative sheet" fol'ding re- =lation -with'said bars-in movementof saidoperat i-ing and actuating =1evers in oner direction andaway-from sa idbars in movementiof said 'lever'sin theoppositedirection,"-means =operated by said actuating 'lever for moving sa'iwmovablef fold forming bar a limited distance towa'rd s'afiti'other barwhen said actuatinglever :is moved inv one direct-ion to move-"s'a'idfolding blade s'toward s'aid bar's toengage a 'sheet therebetween foroooperad tion in initially folding' "said she'ety-said means rmoving-saidmovable bar an additionardistance i-ztOWQrdSElid other ban-inmovement' of said actu- -e ating member'insaid"oppositedirtiorkfoftightly i folding -saidiishet betweensaid barsi-whilasaid fioltiingplzvlade*is'. disengaged'afrom the fol drimsaid sheet and movedaway fromsaid barsrandmeans "*"for r'etarding'the speed of-movement'ofz'saidfoldr-ing blade and actuating-*lever'in saidmppoSite-vdirection -for slowlywithdrawin said' foldingblade mfrom thefold-'in-s'aidsheet.

4.-- A-plastic sheet 'folding machinezcomprising a a support; a'heated'folding 'bladey again of fold. *frforming barsmounted -'for.--mo;vementbf. ata'least ;one"-2to\vard *and'i-from. the othenionsesaid supndrt,:52. a pair-mtarmsi.pivoted omsaidasupportand camying said folding bladefor movement toward and from said bars in a direction substantiallyperpendicular to the plane of movement of said one bar, an operatinglever mounted at one end on said support for oscillating movement, anactuating lever connected with said operating lever for oscillationthereby, a link connecting said actuating lever with one of said armsfor moving said folding blade into cooperative sheet folding relationwith said bars in movement of said operating and actuating levers in onedirection and away from said bars in movement of said levers in theopposite direction, cam means operated by said actuating lever formoving said movable fold forming bar a limited distance toward saidother bar when said actuating lever is moved in one direction to movesaid folding blade toward said bars to engage a sheet therebetween forcooperation in initially folding said sheet, said cam means moving saidmovable bar an additional distance toward said other bar in movement ofsaid a'ctu ating member in said opposite direction for tightly foldingsaid sheet between said bars, and sheet engaging and holding means onthe inner faces of said bars for retaining said sheet between said barswhile said folding blade is withdrawn from the fold in said sheet andmoved away from said bars.

5. A plastic sheet folding machine, comprising a support, a heatedfolding blade, a pair of fold forming bars mounted for movement of atleast one toward and from the other on said support, a pair of armspivoted on said support and carrying said folding blade for movementtoward and from said bars in a direction substantially perpendicular tothe plane of movement of said one bar, an operating lever mounted at oneend on said support for oscillating movement, an actuating leverconnected with said operating lever for oscillation thereby, a linkconnecting said actuating lever with one of said arms for moving saidfolding blade into cooperative sheet folding relation with said bars inmovement of said operating and actuating levers in one direction andaway from said bars in movement of said levers in the oppositedirection, a carrier for said movable bar pivoted on said support, a camrotatably mounted on said support, a cam follower on said carrierengaging said cam, and a double ratchet means for rotating said cam inone direction connected with said actuating arm for operation of saidcam in both directions of movement, said cam being formed for operatingsaid carrier to move said movable fold forming bar a limited distancetoward said other bar when said actuating lever is moved in onedirection to move said folding blade toward said bars for engaging andinitially heating and folding a sheet between said bars about saidblade, said cam being formed to move said bar an additional distancetoward said other bar in movement of said actuating member in saidopposite direction for tightly folding and cooling said sheet betweensaid bars while said blade is withdrawn from the fold in said sheet.

6. A plastic sheet folding machine, comprising a supporting frame havinga bar supporting ledge formed on the upper front edge thereof and havingthe lower frame portion extending forwardly in advance of said barsupporting ledge, a fold forming bar mounted on said ledge, a carrierhaving side extensions pivotally connected to said frame and a barsupporting ledge opposite the ledge on said frame, another fold formingbar mounted on the ledge of said carrier in opposed relation to the baron said frame,-said carrier co operating with said frame to provide anopen discharge passage for folded sheets below said carrier in front ofsaid frame, a heated folding blade, arms pivoted at the sides of saidframe mounting said blade for movement to engage a marginal portionthereof between said bars for engaging and forcing a sheet therebetweento heat and form a fold in said sheet, and means for moving said foldingblade and said carrier in timed relation relative to said frame carriedfold forming bar for initially moving said carrier carried bar towardsaid frame carried bar a limited distance in forming said fold in saidsheet, and said means moving said carrier carried bar closer to saidframe carried bar in further operation to tightly form and cool the foldin said sheet whilejsaid blade is withdrawn from said fold.

7. A plastic sheet folding machine, comprising a supporting frame, apair of arms pivoted on adjustable pivot members carried by said frame,a heated folding blade mounted on said arms, a pair of fold formingbars, one mounted on the ,front of said frame, a carrier pivoted on saidframe mounting the other bar for movement toward and from the bar onsaid frame, means for moving said carrier on its pivot havingcomplementary parts carried by said carrier and said moving meansadjustable to vary the movement of said bar carried thereby relative tosaid bar on said frame to compensate for variations in the thickness ofsheet material to be folded, said pivot members cooperating to adjustthe position of said folding blade for centering said blade between saidfold forming bars in sheet folding cooperation therebetween, andoperating means for oscillating said folding blade toward and from aposition with a margin thereof between said bars for heating and foldinga sheet therebetween, and also operating said means for moving saidcarrier to move said bar thereon toward the other bar a limited initialdistance for cooperation in folding a sheet about the margin of saidfolding blade when engaged therebetween, and said carrier moving saidbar an additional amount toward a said other bar responsive to saidoperating means for forming a tight fold in a sheet between said bars assaid blade is moved away from said bars and disengaged from the fold insaid sheet.

8. A plastic sheet folding machine comprising a pair of parallel foldforming bars, resilient sheet gripping members mounted on opposed facesof said bars, means mounting said bars for relative movement toward andfrom each other, a heated folding blade mounted for movement of amarginal portion thereof substantially perpendicular to theplane ofmovement of said bars to and from a position between said bars, andoperating means for moving said blade and said bars relative to eachother in timed relation whereby said margin of said blade engages asheet supported by said bars and. folds said sheet between said barswhile in spaced relation, said operating means moving said bars towardone another a limited distance in folding the sheet during engagement ofsaid blade margin there,- between with the sheet engaged and retainedbetween said gripping members, and said operating means moving said barsan additional distance toward one another to tightly engage saidgripping members with the folded sheet for holding and tightly foldingsaid sheet while said blade margin is withdrawn from said fold in thesheet.

9. A plastic sheet folding machine, comprising a pair of spaced parallelfold forming bars having longitudinal channels formed in the opposedwasta e in a direction substantial-1yperpendicular-tothe 'planeof said'bar movementtoward and "from a "position' where a margin-pf"said"foldingblade projects between said bars and gripper'strips. and-operatingmeansfor movingsaid blade and ":bars' -=in timed'relation to 'fold a"sheet by first' engaging the marginof said blade with a sheet 9extending *across saidbars and folding "said'sheet between'sa'id bars insaid positionwhere said' blade projects between' said-ba1's'"whi1e"said'-barsare moved toward one another for cooperationin folding saidsheet about said-- blade *margin; and isecondly moving said bars anadditional distance toward each-"cthenfor engaging the inwardly.'projectingportions of said gripper strips with pcirtionsof said foldedsheet at opposite sides "of the fold for-med therein" for tightly'folding said sheet after said blade -marginis withdrawrifrom ssa idfold.

105 A plas'tio'sheet foldingmachine;comprising a" rigid supporting"frame having flat sheet re- "'*ceiving' top portion and side portionsdepending r from the margins there'of, a-'carrier having flat 5 topportion insubstantially coplanar relation to vsaid flat top portion'of'said'frame' in'edge-to-edge r-relation-infront "of said frame; saidcarrier; havtdng depending side" extensions thereon" pivotally mountedat the lower'ends-on the side portions of 1 said "frame for movement 'ofsaid carrier toward fi'aild 'fromsaid frame; a pairvof rfold' formingbars 7' each'mount'edon-one of theopposed'edgesbf said:tframe'andcarrier'top portions inspac'ed parallel ODIJOSed"I'e1ati0Ilandextending between thesides thereof; a heated folding bl'a'de'inspaced parallel relation ito'sa'id'bars, means'm'ou'nting said bladeionsa'idframe a'bovelthe top portion for movement ffrom' a spaced.position to and from a position "where a;*marginiofxsaidiblade extendsbetween said bars, andioperating means for said blade andcarrier-operable tomove the blade to engage a sheet on saidttoprportionsoverzsaid bars and fold said. sheet between .said oars, said operatingmeans initially moving said. carrier ,tozrnovelthe bar thereon a limiteddistance toward the other bar for :cooperationwith said blade in foldingsaid. sheet with said margin of said blade.-posiationed betweenbarswandw saidl wperating zzmeans moving said carrier anadditional.amount i toz move the bar thereon closer to theil'other =bar for tightlygripping and folding said sheet after said operating means has withdrawnsaid blade margin from between said bars and the fold in said sheet.

11. A plastic sheet folding machine, comprising a rigid supporting framehaving a flat sheet supporting top portion and side portions dependingfrom the margins thereof, a carrier having a flat top portion insubstantially coplanar relation to said fiat top portion of said framein edge-to-edge relation in front of said frame, said carrier havingdepending side extensions thereof pivotally mounted at the lower ends onthe side portions of said frame for movement of the carrier top portiontoward and from said frame top portion, a pair of fold forming bars eachmounted on one of the opposed edges of said top portions of said car-Eli-I4 *rierand=frameandmovable therewith imspaced parallel relationtoward and'rfr'omieach dtheni' a pair of arms'each pivoted-Lat:oneiendliomroneziof said frame side portionsaandthavingrfrhevoppdsite 5ends extehdingiabove saidetoplportionfataoppnsite sides thereof; avheateditfoldingzbladezzextendin l betweemandnmounted :omssaidproppositerendssbf said arms aboversaidrframe :top portion fommove- "menttowardrandrfroma a1 pn-sitiontwithlanmargin 10- -'"ofi said .bladepositioned; betweenazsaid zbarsgl san roperating; shaft:-:.;extending";;thronghresaidetframe aside-portions and notatably:monntedrthereinvac-.tuating"- levers mounted 'onrthe lendsrofvsaidashaft Qadjaczehtrthe:outer sides lofesaid:trame-sideeportions, linkscconnectingasaidactuatingnleversrwith :zsaidarms adjacent the outer sidestotsaid frameside portions, means mounted-lomsaidzframelside :5 portions and'operatediby :said -actuat-inglevers for wmoving: zsaid carrier in"timed relation tolzsaid blade; iandl lantgoperating leverzv-mounteduontsaid .ashaftzbetweenisaidlside portions,extendingllaterally; therefrom. ands-manually operable to move zwsaidebladel and 163196181. ton-securing: icooperation ;--of"saidl-bladel-andwpair- .ofbarstinl forming. a fold :5 :in a:sheetplaced H said-itop portions.

125A .plastic :sheetlfolding machine, comprising; aprigidsupporting,fnameshavingt a. flat: sheet asupportingi top portion,aecarrier mounted lfor rocking movementhonathe. front portion lofmsaid:m'. frame and-having; aesheettsupporting top. portion in 7 coplanarredgeetoaedge relation. with ;said .top portion. of.said..frame,ahpairl. of -fold lforlming barseachmounted in opposed relationeonone kof the opposed .edgesiofsaid ltop portions, apair ;ofearms pivotedon.said frame. inpspaced. parallel 1 relatiom. alheatedhfol-dingblademounted onnsaid arms in, spacedparalleLrelationabove saidformaingibarsandmovablewithusaid arms into folding i. cooperation withsaid bars, an, operating fshaft n, rotatable linliand extending Tthrough said" frame, r; actuating .arms mounted .on. said J shaft atoppo- Qsitelsides ofv said frame, links connecting respeclftiveactuating arms with adjacentarmsyand'an operating lever having one endrigidly; secured to the central portion of said operatingslfaft'and"goperable :tounove said "blade and :barsti-nto coop- ,erationforrfdldingi asheettherebetween.

i513." Apl-asticlsheet folding machine,. compris- Tingarig'id-supporting? frame having a flat sheet f'supp0rting topportion;.a carriermounted'pn the "front 'of said'frame for rocking'movement'with portionsin' opposed relation'to portions of' said frame apair ofrforr'ning barsmoun'ted in opposed yparallel -relation oritheopposed portions. of "said frame and 'carrier'f or 'relative'imovementtoward 'and'tfrom =each'other; a pair-"of arms pivoted on T'said'frame*in; spaced parallel relation having cor- :"responding "ends/Projectingabovethe "frame; a folding blademount'ed on and extending between saidcorresponding ends of said arms in parallel relation to said bars andmovable with said arms toward and from folding cooperation with saidbars, actuating levers mounted for rocking movement on said frame, meansconnecting said actuating levers with said pair of arms and said carrierto move said folding blade and carrier in securing a folding operationbetween said blade and said bars and means for changing the relation ofsaid connecting means between said pair of arms and said carrier forvarying the spaced relation of said folding blade and bars in foldingcooperation.

14. A plastic sheet folding machine comprising a heated folding blade, apair of relatively movable fold forming bars, means .movably mountingsaid bars and blade for movement into and out of fold formingcooperation, and operating means for moving said blade and bars informing a fold in sheet material having a rotatable operating shaft, anoperating lever mounted on and extending radially from said shaft, a rodprojecting from said shaft in radial relation and laterally relative tosaid operating lever, a weight mounted on said rod for normally rotatingsaid shaft in one direction to hold said operating lever in a startingposition, and a dash pot for controlling the speed of rotation of saidshaft by said weight, said operating lever being manually operable forrotating said shaft in an opposite direction, said operation of saidshaft in opposite directions moving said blade and bars into and out offold forming cooperation.

15. A plastic sheet folding machine, comprising a rigid supporting framehaving a fiat sheet supporting top portion. a pair of fold forming barsarranged in opposed spaced parallel relation, means mounting one of saidbars on a marginal edge of said top portion, means mounting the other ofsaid bars for movement toward and from said first-mentioned bar inaligned relation with and beyond said first mentioned bar and flat topportion, a folding blade having a narrow forming edge, means mounted onthe sides of said frame mounting said folding blade above said bars inparallel spaced relation with said forming edge projecting toward saidbars, an operating lever pivoted on said support at one end and havingthe opposite end depending therefrom, and means mounted on said framebelow said flat top portion having operative connection with saidfolding blade and movable bar actuated by said operating lever in manualoperation on said pivot for moving said folding blade to engage a sheetsupported on said bars and flat top portion, fold it between said spacedbars and move said other bar toward said first bar in timed relation tosaid folding blade movement for folding cooperation to complete theformation of a folded sheet from a flat sheet.

16. A plastic sheet folding machine, comprising a supporting framehaving a flat sheet supporting top portion, a pair of fold forming barsmounted on said frame, one bar being mounted on a marginal edge of saidtop portion, means i operating lever, a link connecting said arm withsaid folding blade for moving said blade in manual movement of saidoperating lever and means on said frame below said top portion operatedby said operating lever for proportionately moving said movable foldforming bar toward said firstmentioned folding bar in timed relation tooperation of said folding blade for folding a sheet supported on the topof said bars and top portion between said bars and said bars cooperatingto hold and complete said fold in further proportionate movement of saidone bar toward the other.

17. A plastic folding machine, comprising a supporting frame having aflat sheet supporting top portion, a pair of fold forming bars mountedin spaced parallel opposed relation along the front edge of said topportion, one of said bars being rigidly mounted along said marginaledge, means mounted on said frame below said top portion mounting theother bar for movement toward and from the first-mentioned bar, afolding blade, means mounting said folding blade in edgewise relation tosaid bars in spaced relation above said bars for movement toward andfrom a position with the lower edge between said bars for sheet foldingcooperation therewith, said means being mounted on said frame below saidtop portion, an operating lever pivotally mounted at one end on saidframe below said top portion with the free end in downwardly extendingrelation, actuating means carried by said frame below said top portionconnected with said movable bar and operating lever for moving saidmovable bar a limited amount toward said other folding bar in initialoperation of said operating lever, link means operatively connectingsaid operating lever with said blade mounting means for simultaneouslymoving said blade to engage and fold a sheet I supported on said barsand top portion between said bars while said movable bar is moved saidlimited amount in said initial operation of said operating lever, andsaid actuating and link means being operated in further operation ofsaid operating lever to move said movable bar toward said other bar anadditional amount while said blade is moved from its position betweensaid bars for completing the fold in said sheet.

RALPH F. TABER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 503,292 Niedringhaus et al. Aug.15, 1893 2,114,621 Bergstein Apr. 19, 1938 2,339,304 Von Haase Jan. 18,1944

